Abstract
The methanol-to-olefins (MTO) process has the potential to bridge future gaps in the supply of sustainable lower olefins. Promoting the selectivity of propylene and ethylene and revealing the catalytic role of active sites are challenging goals in MTO reactions. Here, we report a novel heteroatomic silicoaluminophosphate (SAPO) zeolite, SAPO-34-Ta, which incorporates active tantalum(V) sites within the framework to afford an optimal distribution of acidity. SAPO-34-Ta exhibits a remarkable total selectivity of 85.8% for propylene and ethylene with a high selectivity of 54.9% for propylene on full conversion of methanol at 400 °C. In situ and operando synchrotron powder X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy and inelastic neutron scattering, coupled with theoretical calculations, reveal trimethyloxonium as the key reaction intermediate, promoting the formation of first carbon-carbon bonds in olefins. The tacit cooperation between tantalum(V) and Brønsted acid sites within SAPO-34 provides an efficient platform for selective production of lower olefins from methanol.
| Original language | English |
|---|---|
| Pages (from-to) | 694-703 |
| Number of pages | 10 |
| Journal | Science Bulletin |
| Volume | 70 |
| Issue number | 5 |
| DOIs | |
| State | Published - Mar 15 2025 |
Funding
We thank the University of Manchester, the National Natural Science Foundation of China and BNLMS for funding, and the EPSRC for funding of the EPSRC National EPR Facility at Manchester (EP/W014532/1 and EP/X034623/1). We are grateful to the STFC/ISIS Facility and Diamond Light Source for access to the beamlines TOSCA/MAPS, and I11/B18/B22, respectively. We acknowledge the UK catalysis Hub Block Allocation Group (BAG) Programme Mode Application for provision of beamtime at B18 for collection of the data presented in this work and the initial discussion of the data. The UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC grant: EP/R026939, EP/R026815, EP/R026645, EP/R027129 and EP/M013219 (biocatalysis). We acknowledge the support of The University of Manchester's Dalton Cumbrian Facility (DCF), a partner in the National Nuclear User Facility. We recognise Dr. R. Edge for the assistance during the 60Co γ-irradiation processes. We thank M. Kibble for help at ISIS beamlines. TEM access was supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X, EP/S019367, EP/P025021 and EP/P025498. Zhaodong Zhu thanks the President's Doctoral Scholar award of University of Manchester for funding. Meng He and Lutong Shan thank the China Scholarship Council (CSC) for funding. Sihai Yang directed and supervised the research. Zhaodong Zhu and Mengtian Fan carried out zeolites synthesis, characterization, and catalysis. Zhaodong Zhu carried out the catalyst stability test. Zhaodong Zhu, Mengtian Fan, Meredydd Kippax-Jones and Mark D. Frogley collected and analysed the DRIFTS data. Zhaodong Zhu, Meng He, Yinlin Chen and Tianze Zhou collected and analysed the SPXRD data. Zhaodong Zhu, Yongqiang Cheng, Hamish Cavaye, Jeff Armstrong, Svemir Rudić and Stewart F. Parker collected and analysed the neutron scattering data. Meng He, Zhaodong Zhu and Mengtian Fan collected and analysed the AFM and SEM data. Zhaodong Zhu, William Thornley, Evan Tillotson, Matthew Lindley and Sarah J. Haigh collected and analysed the TEM data. Zhaodong Zhu, Bing An and Shaojun Xu collected and analysed the XAS data. Zhaodong Zhu, Alena M. Sheveleva, Floriana Tuna and Eric J. L. McInnes collected and analysed EPR data. Zhaodong Zhu, Mengtian Fan and Daniel Lee collected and analysed the ssNMR data. Shenglong Tian, Zhaodong Zhu and Shiyu Fu collected and analysed the ICP data. Lutong Shan conducted DFT calculations. Zhaodong Zhu and Sihai Yang prepared the manuscript with contributions from all authors. Supplementary information is available in the online version of the paper. The raw time-of-flight TOSCA and MAPS spectra are available from: https://doi.org/10.5286/ISIS.E.RB2220046 and https://doi.org/10.5286/ISIS.E.RB2220047, respectively. Crystallographic data for the structures reported in this paper have been deposited at the Cambridge Crystallographic Data Centre under deposition numbers CCDC 2289811, 2289812, 2289813 and 2289814. Copies of the data can be obtained free of charge from www.ccdc.cam.ac.uk/structures/. We thank the University of Manchester, the National Natural Science Foundation of China and BNLMS for funding, and the EPSRC for funding of the EPSRC National EPR Facility at Manchester (EP/W014532/1 and EP/X034623/1). We are grateful to the STFC/ISIS Facility and Diamond Light Source for access to the beamlines TOSCA/MAPS, and I11/B18/B22, respectively. We acknowledge the UK catalysis Hub Block Allocation Group (BAG) Programme Mode Application for provision of beamtime at B18 for collection of the data presented in this work and the initial discussion of the data. The UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC grant: EP/R026939, EP/R026815, EP/R026645, EP/R027129 and EP/M013219 (biocatalysis). We acknowledge the support of The University of Manchester’s Dalton Cumbrian Facility (DCF), a partner in the National Nuclear User Facility. We recognise Dr. R. Edge for the assistance during the 60Co γ-irradiation processes. We thank M. Kibble for help at ISIS beamlines. TEM access was supported by the Henry Royce Institute for Advanced Materials, funded through EPSRC grants EP/R00661X, EP/S019367, EP/P025021 and EP/P025498. Zhaodong Zhu thanks the President’s Doctoral Scholar award of University of Manchester for funding. Meng He and Lutong Shan thank the China Scholarship Council (CSC) for funding.
Keywords
- Inelastic neutron scattering
- Methanol-to-olefin
- Propylene
- SAPO-34
- Trimethyloxonium